The present invention relates to apparatus and method for applying tensioned elastic to material, and more specifically to apparatus and method for applying elongate tensioned elastic members transversely to a moving web of material.
The application of elongate tensioned elastic extending transversely of a moving flow path has been less than completely satisfactory with previously known apparatus and methods. Many previously known devices and methods have used apparatus which requires that the moving web of material stop, or slow down substantially, and then start, or speed up, again to permit transference of the elastic onto material. Other methods and equipment may permit a material web to run continuously, but only at relatively low speeds. Yet others use apparatus and methods which may provide adequate operation for applying tape-like materials, but are less desirable for applying tensioned elastic strands.
A general object of the present invention is to provide novel apparatus which permits high-speed application of elongate elastic transverse onto a high-speed continuously moving material web.
More specifically, an object of the invention is to provide apparatus in which material to have elastic applied thereto is carried by a first conveyor in one direction along a flow path. An elastic conveyor extending transversely of the material flow path is operable to continuously draw elastic from storage, tension it and carry it into a position extending transversely of and spaced from the flow path. A transverse elastic applicator positioned adjacent the first conveyor receives elastic substantially continuously from the elastic conveyor and moves it toward the flow path. The elastic applicator has spaced guide members mounted adjacent opposite sides of the flow path to hold tensioned elastic extending therebetween and transversely of the flow path. The guide members are also operable to hold the tensioned elastic in position as the elastic applicator moves the elastic to the flow path and applies the elastic to the material on the first conveyor. Cutters positioned inboard of the guide members sever the elastic from the guide members after it has been applied to the material.
Another object of the present invention is to provide novel apparatus in which elongate tensioned elastic can be substantially continuously provided extending transversely of a moving web of material which may be used to produce a garment. The apparatus is suitable for application of elastic at high working speeds without the need for interruption or intermittent operation of the moving web of material. It is especially well adapted for the application of the waist zone elastics to disposable diapers or similar products. Such apparatus comprises an elastic feeder positioned adjacent the elastic applicator and operable to receive elastic from the elastic conveyor. The feeder has a feeder head reciprocatively movable in a feeder path extending transversely of the flow path and cooperable with the movement of the elastic applicator to thread elastic onto the applicator in a continuous "square wave" pattern.
Another object of the invention is to provide a novel method for applying elongate tensioned elastic to material moving in one direction along a flow path with the elastic extending transversely of the flow path. The method includes the steps of drawing an elongate section of elastic from a quantity of elastic, stretching the section of elastic to a desired tension, and feeding the elastic reciprocatively in transverse portions between opposed first and second ends of a feeder path that is oriented substantially transversely of the flow path. The elastic is alternately grasped in first and second elastic end regions, respectively, adjacent the first and second feeder path ends as the elastic is fed adjacent the first and second feeder path ends while simultaneously moving the grasped first and second end regions toward the flow path. Movement of the grasped first and second end regions is halted when the elastic is fed transversely across the feeder path between the opposing first and second feeder path ends. The transverse portions are deposited onto the material and cut inboard of the grasped first and second end regions.